COMPOSITIONS USEFUL FOR FORMING SOFT TOUCH COATINGS

Abstract

Soft feel coatings are obtained by curing a coating composition containing a) at least one (meth)acrylate-functionalized oxetane/oxolane oligomer such as a (meth)acrylate-functionalized polytetramethylene ether, b) at least one radiation-curable compound (other than (meth)acrylate-functionalized oxetane/oxolane oligomer) and c) at least one surface conditioner additive selected from the group consisting of particulate surface modification agents and slip additives. As a consequence of containing (meth)acrylate-functionalized oxetane/oxolane oligomer, the coating composition has advantageously low viscosity and yet is capable of providing a cured coating having excellent haptic properties.

Claims

1. A coating composition useful for forming a soft touch coating on a surface of a substrate, wherein the coating composition comprises: a) at least one (meth)acrylate-functionalized oxetane/oxolane oligomer selected from the group consisting of (meth)acrylate-functionalized polytrimethylene ethers, (meth)acrylate-functionalized polytetramethylene ethers, (meth)acrylate-functionalized poly-co-tetramethylene-trimethylene ethers; b) at least one radiation-curable compound other than (meth)acrylate-functionalized oxetane/oxolane oligomer; and c) at least one surface conditioner additive selected from the group consisting of slip additives and particulate surface modification agents d) optionally, at least one photoinitiator, said photoinitiator d) being either one photoinitiator which absorbs both long and short wavelength ultraviolet radiation or said photoinitiator d) is comprising a first photoinitiator which absorbs long wavelength ultraviolet radiation and a second photoinitiator which absorbs short wavelength ultraviolet radiation.

2. The coating composition of claim 1, wherein the coating composition comprises at least one photoinitiator d).

3. The coating composition of claim 1, wherein the at least one (meth)acrylate-functionalized oxetane/oxolane oligomer a) is a di(meth)acrylate-functionalized polytetramethylene ether.

4. The coating composition of claim 1, wherein the at least one (meth)acrylate-functionalized polytetramethylene ether is an acrylate-functionalized polytetramethylene ether.

5. The coating composition of claim 1, wherein the at least one (meth)acrylate-functionalized oxetane/oxolane oligomer a) corresponds to formula (I):
H.sub.2CC(R)C(O)O[(CH.sub.2).sub.xO].sub.nC(O)C(R)CH.sub.2 (I) wherein R and R are independently selected from the group consisting of hydrogen and methyl, x is 3 or 4 and n is an integer of from 2 to 100.

6. The coating composition of claim 5, wherein R and R are both hydrogen.

7. The coating composition of claim 5, wherein the at least one (meth)acrylate-functionalized oxetane/oxolane oligomer is a mixture of (meth)acrylate-functionalized polytetramethylene ethers of formula (I) wherein n is from about 3 to about 42 on average.

8. The coating composition of claim 1, wherein the at least one (meth)acrylate-functionalized oxetane/oxolane oligomer is from about 40% to about 95% by weight of the total amount of (meth)acrylate-functionalized oxetane/oxolane oligomer(s) a) and radiation-curable compound(s) b) other than (meth)acrylate-functionalized oxetane/oxolane oligomer in the coating composition.

9. The coating composition of claim 1, wherein the at least one surface conditioner additive c) comprises at least one slip additive selected from the group consisting of polysiloxanes, natural and synthetic waxes and fluoropolymers, wherein the slip additive may optionally comprise at least one radiation-curable double bond.

10. The coating composition of claim 1, wherein the at least one surface conditioner additive c) comprises at least one polysiloxane selected from the group consisting of silicone polyether copolymers and silicone acrylates.

11. The coating composition of claim 1, wherein the coating composition is comprised of from 0.2 to 20 percent by weight of slip additive.

12. The coating composition of claim 1, wherein the at least one radiation-curable compound b) other than (meth)acrylate-functionalized oxetane/oxolane oligomer, comprises at least one (meth)acrylate-functionalized monomer or oligomer selected from the group consisting of (meth)acrylate esters of aliphatic mono-alcohols, (meth)acrylate esters of alkoxylated aliphatic mono-alcohols, (meth)acrylate esters of aliphatic polyols, (meth)acrylate esters of alkoxylated aliphatic polyols. (meth)acrylate esters of aromatic alcohols, (meth)acrylate esters of alkoxylated aromatic alcohols, epoxy (meth)acrylates, polyether (meth)acrylates, urethane (meth)acrylates, polyester (meth)acrylates and amine- and sulfide-modified derivatives thereof and combinations thereof.

13. The coating composition of claim 1, wherein the at least one radiation-curable compound b) other than (meth)acrylate-functionalized oxetane/oxolane oligomer, comprises at least one (meth)acrylate-functionalized substance selected from the group consisting of di(meth)acrylate-functionalized aliphatic diols which includes di(meth)acrylate-functionalized alkoxylated aliphatic diols.

14. The coating composition of claim 1, wherein the at least one radiation-curable compound b) other than (meth)acrylate-functionalized oxetane/oxolane oligomer, comprises at least one (meth)acrylate-functionalized substance selected from the group consisting of di(meth)acrylate-functionalized propoxylated neopentyl glycol and di(meth)acrylate-functionalized C.sub.8-C.sub.22 aliphatic diols.

15. The coating composition of claim 1, wherein the coating composition is comprised of 50 to 99 percent by weight in total of (meth)acrylate-functionalized oxolane/oxetane oligomer a) and radiation-curable compound b).

16. The coating composition of claim 1, wherein the at least one surface conditioner additive c) comprises at least one particulate surface modification agent selected from the group consisting of silicas, polymer beads and wax particles.

17. The coating composition of claim 1, wherein the coating composition is comprised of from 0.2 to 30 percent by weight particulate surface modification agent.

18. The coating composition of claim 1, wherein the coating composition comprises at least one slip additive and at least one particulate surface modification agent.

19. The coating composition of claim 1, wherein the coating composition comprises at least one slip additive and at least one silica as a particulate surface modification agent.

20. The coating composition of claim 1, wherein the coating composition comprises at least one polysiloxane as a slip additive and at least one silica as a particulate surface modification agent.

21. The coating composition of claim 1, wherein the coating composition comprises at least one photoinitiator d) and wherein the at least one photoinitiator comprises at least one photoinitiator selected from the group consisting of alpha-hydroxy ketones, phenylglyoxylates, benzyldimethylketals, alpha-aminoketones, mono-acyl phosphines, bis-acyl phosphines, metallocenes, phosphine oxides, benzoin ethers and benzophenones and combinations thereof.

22. The coating composition of claim 1, wherein the coating composition comprises a single photoinitiator d) which is capable of absorption of both short wavelength ultraviolet radiation and long wavelength ultraviolet radiation.

23. The coating composition of claim 1, wherein the coating composition is comprised of a first photoinitiator which is capable of absorption of short wavelength ultraviolet radiation and a second photoinitiator which is capable of absorption of long wavelength ultraviolet radiation.

24. The coating composition of claim 1, wherein the coating composition is comprised of from 0.1 to 10 percent by weight of photoinitiator d).

25. The coating composition of claim 1, wherein the coating composition is comprised of not more than 1% by weight in total of non-reactive solvent and water.

26. A method of forming a soft touch coating on a surface of a substrate, comprising applying a layer of the coating composition of claim 1 to at least a portion of the surface and curing the coating composition by irradiation.

27. The method of claim 26, wherein the substrate is comprised of a material selected from the group consisting of thermoplastics, thermoset resins, ceramics, cellulosic materials, leather and metals.

28. The method of claim 26, wherein the layer of the coating composition has a thickness of from 10 to 75 microns.

29. The method of claim 26, wherein the curing is performed by exposing the coating composition to at least one source of radiation selected from ultraviolet radiation and/or electron beam radiation.

30. The method of claim 26, wherein the layer of the coating composition is cured by first exposing the layer of the coating composition to long wavelength ultraviolet radiation and then exposing the layer of the coating composition to short wavelength ultraviolet radiation and wherein the coating composition is comprised of at least one photoinitiator which absorbs both long and short wavelength ultraviolet radiation or is comprised of a first photoinitiator which absorbs long wavelength ultraviolet radiation and a second photoinitiator which absorbs short wavelength ultraviolet radiation.

31. A substrate having a soft touch coating obtained by curing a coating composition in accordance with claim 1.

Description

EXAMPLES

Examples 1, 1B and 2

[0110] Three different coating compositions were prepared, in accordance with the following formulations (Tables 1-3). The silica used in each composition was a polymer-treated thermal silica (alternatively described as a polysiloxane-coated fumed silica). The slip additive used in each composition was a polyether siloxane copolymer (alternatively described as a polyether siloxane).

Example 1

[0111]

TABLE-US-00001 TABLE 1 Component Mass (g) Weight % Diacrylate-Functionalized 24.00 52.46 Polytetramethylene Ether (M.sub.n = ca. 650 g/mol) Propoxylated Neopentyl 16.00 34.97 Glycol Diacrylate Dispersant (structured acrylic 0.35 0.77 copolymer) Silica 3.40 7.43 2-Hydroxy-2-methyl-1-phenyl- 2.00 4.37 1-propanone Total 45.75 100.00

Example 1B

[0112]

TABLE-US-00002 TABLE 2 Component Mass (g) Weight % Diacrylate-Functionalized 24.00 51.68 Polytetramethylene Ether (M.sub.n = ca. 650 g/mol) Propoxylated Neopentyl 16.00 34.45 Glycol Diacrylate Dispersant (structured acrylic 0.35 0.76 copolymer) Silica 3.40 7.32 2-Hydroxy-2-methyl-1-phenyl- 2.00 4.31 1-propanone Slip Additive 0.69 1.48 Total 46.44 100.00

Example 2

[0113]

TABLE-US-00003 TABLE 3 Component Mass (g) Weight % Diacrylate-Functionalized 39.00 51.22 Polytetramethylene Ether (M.sub.n = ca. 650 g/mol) Propoxylated Neopentyl Glycol 26.00 34.15 Diacrylate Dispersant (structured acrylic 0.57 0.75 copolymer) Silica 5.53 7.26 Diphenyl(2,4,6- 1.95 2.56 trimethylbenzoyl)phosphine oxide 70:30 (w/w) blend of oligo[2- 1.95 2.56 hydroxy-2-methyl-1-[4-(1- methylvinyl)phenyl]propanone] and 2-hydroxy-2-methyl-1-phenyl-1- propanone Slip Additive 1.14 1.50 Total 76.14 100.00

[0114] The aforementioned formulations were drawn down on substrates as 1 mil thickness coatings and photocured using different conditions, as summarized in the following Table 4. The results obtained for the cured coatings are also described in the table.

TABLE-US-00004 TABLE 4 Formulation Example Cure Conditions Feel Gloss 1 2 Mercury arc lamps, 400 W/in, Not Soft 31.7 50 fpm .sup.1B 2 Mercury arc lamps, 400 W/in, Not Soft 33.9 50 fpm 2 V lamp 600 W/in + 2 passes under 2 Velvety 10.4 Mercury arc lamps, 50 fpm 2 V lamp 400 W/in + 2 passes under 2 Velvety 8.8 Mercury arc lamps, 50 fpm 2 395 nm LED 12 W/in + 2 passes Velvety 8.2 under 2 Mercury arc lamps, 50 fpm 2 395 nm LED 6 W/in + 2 passes Velvety 5.9 under 2 Mercury arc lamps, 50 fpm

Example 3 (Comparative)

[0115] The following formulation (Table 5) was prepared as a coating composition.

TABLE-US-00005 TABLE 5 (Example 3) Component Mass (g) Weight % Acrylate Oligomer (Isocyanurate 15.76 47.44 Derivative) Lauryl Acrylate 7.88 23.72 Propoxylated Neopentyl Glycol 5.25 15.81 Diacrylate Dispersant 0.22 0.67 Silica 2.17 6.52 2-Hydroxy-2-methyl-1-phenyl-1- 1.44 4.35 propanone Slip Additive (Polyether Siloxane 0.49 1.48 Copolymer) Total 33.22 100.00

[0116] The coating composition of Example 3 was drawn down to a thickness of 3 mil on a substrate and photocured using the conditions shown in Table 6.

TABLE-US-00006 TABLE 6 Formulation Example Cure Conditions Feel Gloss 3 2 Mercury arc lamps, 400 W/in, Not Soft 38.2 50 fpm 3 V lamp 600 W/in + H lamp 600 W/in, Velvety/ 6.7 50 fpm Silky

Example 4

[0117] A coating composition was prepared based on the following formulation (Table 7):

TABLE-US-00007 TABLE 7 (Example 4) Component Mass (g) Weight % Diacrylate-Functionalized 12.00 50.35 Polytetramethylene Ether (M.sub.n = ca. 650 g/mol) Propoxylated Neopentyl Glycol 8.00 33.57 Diacrylate Dispersant (structured acrylic 0.18 0.74 copolymer) Silica 1.70 7.13 1-Hydroxy-cyclohexyl-phenyl- 0.90 3.78 ketone 2,4,6-Trimethylbenzoyl-diphenyl 0.30 1.26 Phosphine Oxide Mixture of Benzophenones and 0.40 1.68 Methylbenzophenones Slip Additive (Polyether Siloxane 0.36 1.50 Copolymer) Total 23.83 100.00

Example 5

[0118] A coating composition was prepared based on the following formulation (Table 8):

TABLE-US-00008 TABLE 8 (Example 5) Component Mass (g) Weight % Diacrylate-Functionalized 12.00 51.67 Polytetramethylene Ether (M.sub.n = ca. 650 g/mol) Propoxylated Neopentyl Glycol 8.00 34.45 Diacrylate Dispersant (structured acrylic copolymer) 0.18 0.76 Silica 1.7 7.32 50:50 Blend of 1-Hydroxy-cyclohexyl- 1 4.31 phenyl-ketone and Benzophenone Slip Additive (Polyether Siloxane 0.35 1.50 Copolymer) Total 23.22 100.00

[0119] The coating compositions of Examples 1B, 2, 4 and 5 were drawn down to a thickness of 3 mil on a substrate and photocured using the conditions described in the following Table 9.

TABLE-US-00009 TABLE 9 Formulation Example Cure Conditions Feel Gloss 1B V lamp 600 W/in + H lamp Velvety 1.4 600 W/in, 50 fpm 4 V lamp 600 W/in + H lamp Velvety 3.2 600 W/in, 50 fpm 2 V lamp 600 W/in + H lamp Velvety/Rubbery 1.4 600 W/in, 50 fpm 5 V lamp 600 W/in + H lamp Velvety 2.0 600 W/in, 50 fpm

Examples 6-8

[0120] Coating compositions were prepared based on the formulations described in Tables 10-12.

TABLE-US-00010 TABLE 10 (Example 6) Component Mass (g) Weight % Diacrylate-Functionalized 24.00 51.67 Polytetramethylene Ether (M.sub.n = ca. 650 g/mol) Long Chain Aliphatic 16.00 34.44 Diacrylate Dispersant (structured acrylic 0.35 0.76 copolymer) Silica 3.40 7.32 2-Hydroxy-2-methyl-1-phenyl- 2.00 4.31 1-propanone Slip Additive (Polyether 0.70 1.51 Siloxane Copolymer) Total 46.45 100.00

TABLE-US-00011 TABLE 11 (Example 7) Mass Component (g) Weight % Polyester Acrylate Oligomer (based 24.00 50.39 on caprolactone) Propoxylated Neopentyl Glycol 16.00 33.59 Diacrylate Dispersant (structured acrylic 0.35 0.74 copolymer) Silica 3.40 7.14 1-Hydroxy-cyclohexyl-phenyl-ketone 1.80 3.78 2,4,6-Trimethylbenzoyl-diphenyl- 0.60 1.26 phosphine Oxide Mixture of Benzophenone and 0.80 1.68 Methylbenzophenones Slip Additive (Polyether Siloxane 0.68 1.43 Copolymer) Total 47.63 100.00

TABLE-US-00012 TABLE 12 (Example 8) Component Mass (g) Weight % Alkoxylated Trimethylolpropane 24.00 50.39 Triacrylate Propoxylated Neopentyl Glycol 16.00 33.59 Diacrylate Dispersant (structured acrylic 0.35 0.74 copolymer) Silica 3.40 7.14 1-Hydroxy-cyclohexyl-phenyl-ketone 1.80 3.78 2,4,6-Trimethylbenzoyl-diphenyl- 0.60 1.26 phosphine Oxide Mixture of Benzophenone and 0.80 1.68 Methylbenzophenones Slip Additive (Polyether Siloxane 0.68 1.43 Copolymer) Total 47.63 100.00

[0121] The coating compositions of Examples 1B, 3 and 6-8 were drawn down to a thickness of 3 mil on a substrate and photocured using first a V lamp (600 W/in) followed by an H lamp (600 W/in) at 50 fpm.

[0122] The coating compositions of Examples 1B, 3 and 6-8, when uncured, had the viscosities at 25 C. as shown in Table 13.

TABLE-US-00013 TABLE 13 Example Viscosity, mPa .Math. s (cP) at 25 C. 1B 790 6 2960 7 2083 8 1410 3 13,820

[0123] Table 14 shows various attributes of the cured coatings obtained using the coating compositions of Examples 1B, 3 and 6-8.

TABLE-US-00014 TABLE 14 Pencil MEK Example Feel Hardness Gloss Resistance Quality 1B Velvety 4B 8.4 85 4 6 Rubbery/Velvety 3B 6.4 200+ 4.5 7 Silky 6H 1.6 200+ 3.5 8 Velvety HB 5.6 53 2.5 3 Velvety 4B 3.1 86 4.5

[0124] The properties reported for the Examples were determined using a number of known techniques. Pencil hardness values were determined in accordance with ASTM D3363-05. MEK (mar) resistance was determined in accordance with ASTM D5402-06. Viscosities were measured with a Brookfield viscometer, model DV-II, at 25 C. using a 27 spindle and speed was varied depending on viscosity, typically between 50 and 200 rpm. Gloss was measured with a BYK micro-tri-gloss meter at 60 degree angle.

[0125] The Feel and Quality ratings reported in Table 14 were determined in accordance with the following procedures: the cured coatings of the Examples were compared to commercially available two-part urethane soft feel coatings and were rated by a relatively large pool of experienced observers on type of feel (rubbery, velvety, silky) and softness (1=no soft feel, 5=best soft feel).